Oil-soluble polymers and compositions containing them



United States Patent 3,337,458 OIL-SOLUBLE POLYMERS AND COMPOSITIONS CONTAINING THEM La Verne N. Bauer, Cheltenham, and Gordon L. Willette,

Philadelphia, Pa., assignors to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Filed Apr. 4, 1966, Ser. No. 539,633

18 Claims. (Cl. 252--48.6)

This application is a continuation-in-part of United States application Ser. No. 516,137 filed on Dec. 23, 1965, now abandoned.

This invention deals with novel oil-soluble polymers and lubricating and fuel compositions containing them.

More particularly, this invention concerns oil-soluble polymers and compositions containing them wherein said polymers contain at least 0.5% and up to about 60% by Weight of a sulfoxide-containing monomer containing the group where R is an alkyleneoxy group of 2 to 5 carbon atoms or a mixture of these alkyleneoxy groups,

R" is an alkyl group of 1 to 18 carbon atoms, X is hydrogen or methyl, and n is an integer having a value of 1 to 50.

The valuable polymers of the present invention act as dispersants, pour-point depressants, anti-corrosion agents, viscosity-index improvers, or in any two or more of these capacities simultaneously when incorporated in a suitable petroleum product wherein said polymers constitute at least 0.001% of the total weight of the composition. Said polymers are particularly valuable as sludge dispersants when incorporated in a lubricating oil to be used in the crankcase of a spark ignition engine.

In order to keep pace with the rapid improvements in the various internal combustion engines, especially those used in automobiles and trucks, there has been a great deal of attention directed to the betterment of the lubricants used in these engines. Of course, as is well known in the art, the improvements in said lubricant have been brought about by the incorporation of various additives into petroleum oils suitable for lubrication purposes. The additives used in any particular oil composition are dependent upon the properties sought to be obtained in such composition. Generally, such additives make up a minor portion of the lubricating composition.

As is well known in the art, deposits form on engine surfaces due to a variety of reasons. While certain additives, especially metal containing salts, and the oil itself have contributed to the formation of deposits on engine surfaces, the major sources of such deposits consist of the various aldehydes, acids, oxy-acids and other similarly reactive, partially-oxidized combustion products of the fuel. Many of these combustion products are carried into the crankcase of the engine along with other blow-by gases. These products are generally insoluble or only partially soluble in oil and, therefore, they tend to sepa rate from the oil and adhere to engine surfaces. In any event, under the elevated temperature conditions prevailing in the engine, these oxidation products quickly polymerize to form solid masses which readily deposit out on the engine surfaces.

In addition to the problem of engine deposits, the combustion products of the fuel cause excessive wear of piston rings and cylinder walls. This wear is especially prevalent where the engine is operating under relatively cold conditions, that is, at temperatures below about 150 ice F. At these temperatures, there is an accumulation of moisture and acid products on the engine surfaces and it is this accumulation which promotes the wear on said engine parts.

The oil additives used to counteract these problems are generally known as detergents or dispersants. The desirable characteristics of a detergent or dispersant are that it be capable of solubilizing or emulsifying in the lubricant, in which it is incorporated, large amounts of all the Various partial oxidation products of the fuel which might -be carried into the oil and also the ability to maintain in suspension in the oil the various solid polymeric materials, which are present therein. In addition, such detergent or dispersant should be capable of being mixed with various other additives which might be used in any particular lubricating composition. Also, such detergent or dispersant should be free of metals so as not to be a source of engine deposits in itself. It is also quite important that a detergent or dispersant be capable of rendering its detergent or dispersant characteristics over an extended period of time.

The polymers of the present invention possess the enumerated characteristics to a high degree and, therefore, they prove to be extremely useful additives for lubricating compositions. They are particularly valuable when incorporated in lubricating compositions which are to be used in internal combustion engines requiring a lubricant which will permit the engine to be operated at a high level of efliciency over long periods of time.

The polymers of the present invention are free of metals or any other inorganic components which give ash. Therefore, they will not have a tendency to form deposits themselves as a result of decomposition at high temperatures.

There has been a great deal of activity with regard to the search for ash-free oil-soluble polymers having detergent-dispersant properties which could be used in lubrication compositions requiring the retention of said detergent-dispersant properties over an extended period of time. Related art in this area is shown by United States Patents Nos. 2,892,783, 2,925,406, 3,102,863, 3,189,586

and British Patent No. 985,989.

The sulfoxide monomers used in making the polymers of this invention are those of the formula where R is either hydrogen or methyl,

R is an alkyleneoxy group of 2 to 5 carbon atoms, such R" is an alkyl group of 1 to 18 carbon atoms, preferably 1 to 4 carbon atoms,

X is hydrogen or methyl, and

n is an integer having a value of 1 to 50,

preferably 1 to 15.

While the polymers provided by the invention may be homopolymers when the units contain long-chained oleophilic groups, which render the polymer oil-soluble, it is generally preferred to prepare copolymers of the sulfoxide monomers with less expensive comonomer suitable for imparting oil-solubility to the resulting copolymer. The term oil-soluble, as employed throughout this specification and the claims, in connection with the polymers of the subject invention, is intended to mean that the polymer in question is soluble in a lubricant or fuel base to the extent of at least 0.001% by Weight. The following may be used as a base:

(a) A hydrocarbon fuel, such as gasoline or kerosene,

(b) A hydrocarbon oil, such as diesel fuel, heating oil or lubricating oil,

(c) A synthetic lubricating oil base comprising esters or polyesters, and

(d) A hydraulic fluid comprising hydrocarbons and/ or esters.

The comonomers selected in preparing the copolymers of the present invention will, of course, be dictated by many variables, such as the expense involved, their oilsolubility, the sulfoxide monomer with which they are to be copolymerized and others, as will be understood by those skilled in the art. As comonomers suitable for this invention, there may be employed vinyl carboxylates of up to 20 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate and vinyl stearate. In addition, similarly suitable comonomers are esters of a,fi-monoethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid or aconitic acid, with an alkanol having from 1 to 24 carbon atoms, benzyl alcohol, an alkyl-substituted benzyl alcohol or phenol. Preferably, a saturated aliphatic alcohol having from 4 to 18 carbon atoms is employed. However, aralkyl alcohols, such as benzyl alcohol or an alkyl-substituted benzyl alcohol, such as dodecylbenzyl alcohol, are also quite useful.

As previously stated, depending upon the particular sulfoxide monomer used and the particular oil in Which solubility is required, the choice of the comonomer may range from a relatively low molecular weight comonomer, such as methyl acrylate or methacrylate or ethyl acrylate or methacrylate, to an ester having longer chain groups in the alcohol moiety, such as butyl, vamyl, hexyl or cyclohexyl, up to the long-chained alkyl ester having from 8 to 18 or even 24 carbon atoms, which are generally preferred, such as n-octyl, 2-ethylhexyl, t-octyl, decyl, dodecyl, tridecyl, myristyl, cetyl, hexadecyl, octadecyl, eicosyl or docosyl. The comonomer component of the copolymers may advantageously include a mixture of these various ester monomers. Examples of the mixtures include such commercial mixtures as those obtained by esteri-fying methacrylic acid or acrylic acid with a mixed alcohol, such as a mixture of about 70% lauryl alcohol with about 30% of myristyl alcohol. In addition to the simple ester comonomers mentioned, there may be used thioesters obtained from any of the unsaturated acids mentioned and a C to C mercaptan, preferably a C to C mercaptan.

Other typical comonomers which can be worked into the copolymers of this invention in substantial amount include acrylonitrile, vinylidene chloride, styrene, vinyltoluene, a-methylstyrene, dimethyl itaconate, dibutyl itaconate, dioctyl itaconate, didodecyl itaconate, dicetyl itaconate, octadecyl butyl itaconate, didodecyl fumarate, vinyl octanoate, vinyl dodecyl ether, vinyl tetradecyl thioether, vinyl butyl thioether, butoxyethyl methacrylate, dodecyloxyethyl methacrylate and dodecylthioethyl methacrylate. There may also be used small quantities of 01.,[3- ethylenically unsaturated monocarboxylic acids of from 3 to 18 carbon atoms each, or a,5-dicarboxylic acids from 4 to 12 carbon atoms each, or anhydrides, or monoesters, or monoamides thereof. Examples include acrylic acid,

methacrylic acid, itaconic acid, maleic acid and fumaric acid. If desired, the copolymers may contain substantial amounts up to 10 or 15% by weight of nitrogen-containing comonomers, such as vinyl pyrrolidinones, especially N-vinyl-Z-pyrrolidone, N-vinyl piperidinone, a vinyl caprolactam, dimethylaminoethyl acrylate or methacrylate, N (dimethylaminoethyl)acrylamide or N,N dimethylmethacrylamide, N-vinyl succinimide or vinyl pyridines.

The sulfoxide monomers used in forming the polymers of the present invention may be prepared in any suitable manner. One such manner comprises the oxidation of the sulfide atom of corresponding sulfides containing the group or groups in place of the hydrogen of the carboxyl group of acrylic or methacrylic acid or in place of one or more of the hydrogen atoms of the carboxyl groups of maleic, fumaric,

itaconic and aconitic acid. This reaction is shown in the following illustration:

[0] Il -(R)n(l3HCH2sR" (R)n(|3HCH SR See also United States Patents Nos. 2,812,267 and 2,864,-

866 for methods of sulfoxide preparation.

The polymers of the present invention may be produced by polymerizing or copolymerizing the sulfoxide monomers, such as in bulk or in solution. Solution polymerization may be effected in any suitable solvent for the product obtained which, in the case of some of the monomers containing oxyalkylene groups, include Water, ethanol, or acetone, and in the case of the other monomers, may include benzene, toluene, xylenes, kerosene, gasoline, aromatic naphthas, chlorinated hydrocarbons, such as ethylene dichloride, dimethylformamide, esters such as butyl acetate or ethyl propionate, or any of the ester or hydrocarbon liquids within which the polymers are to be used. The solvent may be retained in the final polymer or may be stripped off. It is usually desirable to displace from the final polymer a volatile solvent with a good quality oil, such as SUS- or neutral oil to give an oil solution of the final polymer.

On the other hand, there may be used as a solvent a relatively non-volatile organic liquid such as dibutyl sebacate, dioctyl sebacate, dioctyl azeleate, tributyl phosphate, ltricresyl phosphate, dibutylphenyl phosphate, silicate esters, or silicone fluids. It may be desirable to use such liquids as solvent when the final polymer is to be used in liquids of this sort.

If the polymer is prepared in a volatile solvent, it may be transferred to the oil or relatively non-volatile ester or the like by mixing the solution of polymer and oil or ester and distilling off the volatile solvent. Such mixtures may be heated to 100 to 200 C. at reduced pressures to ensure complete removal of the volatile solvent. During the heating of the mixture, remaining traces of initiator are decomposed.

The polymerization may be effected with the aid of a free-radical initiator or catalyst, such as an organic or inorganic peroxidic catalyst, including peroxides and persulfates, and the azo catalysts. From about 0.05 to 5% or more of the initiator or catalyst may be used, based on the total weight of the monomers. To provide a high molecular weight, it is preferred to use from 0.05 to 1% of the initiator. Examples of organic peroxidic catalysts that may be used include, 2,2-bis-(t-butylperoxy)butane, benzoyl peroxide, methyl ethyl ketone peroxide, acetyl peroxide, caproyl peroxide, lauroyl peroxide, butyl perbenzoate, butyl hydroperoxide, cumene hydroperoxide, pmenthane hydroperoxide, diisopropylbenzene hydroperoxide and other t-alkyl hydroperoxides. Quaternary ammonium activators may be used and are especially valuable with the hydroperoxides. A particularly effective initiator system is developed by using a hydroperoxide together with a quaternary ammonium salt, such as tetra methylammonium chloride, benzyltrimethylammonium chloride, diisobutylphenoxyethoxyethyldimethylbenzylammonium chloride, lauryldirnethylbenzylammonium chloride, lauryldimethylcyclohexylammonium chloride, dodecylbenzyltrimethylammonium bromide, didodecenyldimethylammonium chloride, cetyltrimethylammonium chloride, cetylpyridinium chloride, or other quaternary ammonium salts which have alkyl, alkenyl, cycloalkyl or aralkyl groups as N-substituents. The quaternary ammonium salt may be used in a proportion from about 0.01 to 0.5% of the weight of the polymerizing mixture or preferably from 5 to about 40% of the hyd-roperoxide Weight. The salt acts as an activator and helps to control molecular sizes of the polymer as well as speeding up the rate of polymerization.

Examples of azo catalysts include azodiisobutyronitrile, azodiisobutyramide, dimethyl or diethyl or dibutyl azodiisobutyrate, azobis-(a, -dimethylvaleronitrile, azobis- (ocmethylbutyronitrile azobisa-methylvaleronitrile dimethyl or diethyl azobismethylvalerate and the like.

Polmerization may also be initiated by high-energy irradiation. Suitable sources of high-energy irradiation are radioactive materials and electron accelerators. Useful as radioactive materials that supply gamma rays are irradiated isotopes, such as Co fission products, such as Cs adjuncts to fission reactants, such as radioactive xenon, and the like. A C0 source is particularly effec tive. Useful as radioactive materials that supply beta rays are Sr and the like. Valuable as electron accelerators, which supply beta rays, are the Van de Graaif generator, the resonant transformer, and the like. Dosages in the range of 10,000 to 10,000,000 reps, preferably 500,0000 to 2,000,000 reps, are employed. A rep is equivalent to the ionization produced by the absorption of 93 e-rgs of energy per gram of irradiated substance. Rep stands for roentgen-equivalent-physical and is a unit of intensity and time.

The copolymers provided by the present invention may be prepared by copolymerizing in the manner described above one or more monoethylenically unsaturated polymerizable monomers, which are such as to result in a copolymer which is oil-soluble and which contains 0.5 to about 60% or more by weight of at least one of the sulfoxide monomers of the present invention with one or more of the comonomers previously described.

The expression polymerizable monoethylenically un saturated monomer denotes a compound which contains the vinylene group,

-CH=CH the vinyl group,

CH =CH or the vinylidene group,

advantageously the grouping,

wherein p represents the whole number 1 or 2, and which compounds are homopolymerizable and copolymerizable and also those that are only copolymerizable.

The polymers of the present invention may be added to the liquid hydrocarbon or ester base in proportions of about 0.001% up to 25% by weight based on the total Weight of the composition wherein it serves the purpose of imparting improved properties as enumerated heretofore. Such compositions are employed as lubricants, including line, kerosene, diesel oil, jet engine fuels and hydraulic transmission oils. In a lubricating oil composition wherein the polymer is incorporated to serve as a sludge dispersant, about 0.1 to about 10% by weight of polymer need be added in order to be eflfective. In fuel oils, the proportion of polymer may be in the range of 0.001 to about 1%. More or less than the specified limits of the polymer may be employed in any particular case. However, if more is used, it is generally found to be an unnecessary expense and if less than the lower limit specified is employed, the extent of the effect is generally diminished proportionately.

The hydrocarbon oils referred to throughout this specification may be of a lubricating or fuel type and their composition may constitute paraflinic, naphthenic or aromatic components or any mixtures thereof.

The ester liquids referred to throughout this specification include fatty acid esters of higher alcohols, such as the esters of alcohols from octyl to octadecyl with fatty acids of 1 to 18 or more carbon atoms, and preferably 4 to 18 carbon atoms. Ester liquids may also be diesters of aliphatic dicarboxylic acids, such as the diesters formed from diacids having from 6 to 12 carbon atoms with monohydric alcohols having from 4 to 12 carbon atoms and preferably 6 to 10 carbon atoms, or from mixtures of such alcohols. These include the sebacates, azeleates and the like.

The polymers of the present invention may be incorporated in hydrocarbon or liquid ester compositions, in conventional ways wherein other additives are employed, such as anti-oxidants, stabilizers, wear-resisting agents, other detergents, anti-rust agents, pour-point depressants, viscosity-index improvers, anti-foaming agents or dyes.

The solution obtained when polymerization is effected in a solvent or an oil can be used as a concentrate for addition to the oil to be modified therewith. A concentrate obtained in this manner may conveniently contain up to as much as 70% polymer by weight.

Several standard laboratory tests were employed to determine the dispersant ability of the present materials. Following is a description of the methods and procedures used in conducting said tests.

DISPERSANCY TEST A practical laboratory method for determining the dispersing activity of any given polymer is based on the capacity of this polymer to disperse asphaltenes in a typical mineral oil.

The asphaltenes are obtained by oxidizing a naphthenic oil with air under the influence of a trace of iron salt as catalyst, such as ferric naphthenate. The oxidation is desirably accomplished at 175 C. for 72 hours by passing a stream of air through a naphthenic oil. Pentane is added to the cooled, oxidized oil to form a sludge which may be separated by centrifuging. The sludge is freed from oil by extracting it with pentane. It is then taken up wit-h chloroform and the resulting solution is adjusted to a solids content of about 2% (wt. per vol.).

When a polymer is to be examined for its dispersing activity, it is dissolved in a standard oil, such as a solventextracted neutral. Blends may be prepared to contain percentages varying from about 2 to 0.01% or even lower of polymer in oil.

A 10 ml. sample of a blend is treated with 2 ml. of the standard solution of asphaltenes in chloroform. The sample and reagent are thoroughly mixed in a test tube and the tube is placed in a forced draft oven at C. for 2 hours to drive off volatile material. The tube is then allowed to cool and the appearance of the sample is noted.

If the polymer has dispersing activity, the oil will appear clear although colored. The appearance may then vary from being hazy or turbid to the state in which suspended particles appear, and finally to the point where the asphaltenes appear in a flocculent state. The polymers are rated accordingly.

'2' SUNDSTRAND PUMP TEST In this test for distillate fuel oils, 1 liter of fuel oil containing 4 grams of synthetic sludge is treated with the additive. The oil is circulated for an hour through a Sundstrand oil burner pump containing a 100-mesh strainer. The sludge deposit is collected and weighed (Nelson, Osterhaut and Schwindeman, Ind. Eng. Chem., 48, 1892 (1956)).

API SERVICE MS SEQUENCE V-A TEST This test evaluates the sludge dispersant characteristics of a lubricant under low and medium temperature operating conditions. A single cylinder oil test engine is operated under conditions described in ASTM Special Technical Publication No. 315, published by the American Society for Testing Materials, 1916 Race St., Philadelphia, Pa. 19103.

The engine may be rated at any time during the course of the test. The 7 parts rated for sludge (CRC Merit, 10=clean) are the rocker arm assembly, rocker arm cover plate, valve deck, timing gear cover, push rod cover plate, push rod chamber and oil pan.

The compounds and compositions of the present invention may be more fully understood from the following examples which are offered by way of illustration and not by way of limitation. Parts are by weight unless otherwise indicated.

Example 1 A 500 cc. round bottom 3-neck flask is equipped with a gas inlet tube, a condenser, a circular-type glass stirrer and an addition funnel. The system is flushed with nitrogen and the bath surrounding the reaction vessel is maintained at 90 C. There is added to the reaction vessel a mixture consisting of 93.5 parts of lauryl-myristyl methacrylate (96.3% purity by gas-liquid-chromatography (GLC), representing 90.0 parts of 100% monomer), 10.0 parts of ethylsulfinylpolyethoxyethyl methacrylate (100% purity assumed, containing 6.28 ethoxy units), 50.0 parts of toluene, 1.6 parts of azobisisobutyronitrile (12.5% solution in chloroform) and 0.3 part n-dodecyl mercaptan. The bath is raised around the reaction vessel and in 0.25 hour, the reaction mixture attains a temperature of 90 C. Within 0.08 hour, after attaining 90 C., initiation of polymerization occurs as evidenced by an increase in viscosity. The temperature is maintained at 90 C.i4 C. throughout the polymerization cycle. Additions of 0.8 part of azobisisobutyronitrile (12.5% solution in chloroform) are made at 0.5 hour intervals beginning at 0.5 hour with the final addition of 6.0 hours for a total of 12 additions. Toluene (85.0 parts) is added at 6.33 hours and the polymerization is considered complete at 6.5 hours.

The resulting solution is 39.1% polymer, as determined by precipitation, representing a polymer yield of 96.3%. Sulfur analysis on the precipitated polymer reveals that a quantitative conversion of the sulfur-containing monomer has been achieved.

The polymer is stripped into 100 viscosity neutral oil to give a 29.3% solution with a viscosity of 106.8 cs. at' 210 F. Six-hundred and twenty-five ten thousandths percent of this copolymer in an oil test blend disperses 0.4% asphaltenes at 150 C.

The copolymer of Example 1 is incorporated at a level of 1% by weight in a neutral oil containing 1% zinc dialkyldithiophosphate. Into another sample of the same neutral oil there is incorporated at a level of 1% by weight a copolymer of n-alkylpolyethylene oxide methacrylate, such as described in United States Patent No. 2,892,783.

These two lubricating compositions, hereinafter referred to as Composition A and Composition B, respectively, are then tested for their detergent and dispersant 8 abilities in the API Service MS Sequence V-A Test. The results of this test are given in the following table.

1 ART represents actual running time. 2 A 70.0 rating is equivalent to clean.

As is shown by the Sequence V-A Test, the copolymer of Example 1 is an excellent dispersant in a lubricating oil which retains its dispersant characteristics over an extended period of time. This fact is emphatically evidensed by the comparison of the performance of Com position A with that of Composition B. Bearing in mind that a 70.0 rating is equivalent to clean, a 56.0 rating is not reached until 165 hours has elapsed where Composition A is used, whereas the same rating is achieved at 143 hours with Composition B. The ability of the present invention to retain its dispersant characteristics over greater lengths of time is more fully demonstrated by the fact that a 49.0 rating is not obtained until 199 hours of running time where Composition A is used. However, the 49.0 rating is reached only 5 hours of running time after the 56.0 rating is reached where Composition B is used. This, of course, indicated that Composition B has, 'more or less, lost its dispersant ability.

A similar copolymerization was carried out using ethyl sulfinyl (ethoxyh ethyl methacrylate in place of the monomer containing 6.28 ethoxy units. The polymer so obtained also exhibited outstanding dispersant properties.

Example 2 Apparatus is provided with an efficient stirrer, a thermometer, inlet and outlet tubes for gas and a device for admitting reactants. The polymerization vessel is heated with an electrically heated oil bath and the apparatus is swept with nitrogen throughout the polymerization cycle.

There are mixed in a container:

44.2 parts of lauryl-myristyl methacrylate, (96.3% pure by gas-liquid-chromatography (GLC)),

7.5 parts ethyl su1finyl(ethoxy) ethyl methacrylate,

25.0 parts toluene,

0.1 part of azodiisobutyronitrile (AIBN) in 0.7 part of chloroform and 0.15 part of n-dodecyl mercaptan.

This mixture is charged to the polymerization vessel and heated at 62 to 94 C. and kept as close to C. as possible. Ten minutes after the start of heating, 0.05 part of AIBN in 0.35 part of chloroform is added every 30 minutes for a total of 11 times; at 6 hours, there is added 43 parts of toluene and heating is terminated.

The resulting clear viscous solution analyzes 39.2% of solids as copolymer by precipitation, The solid copolymer contains 1.01% sulfur representing 14.6% of ethylsulfinylpolyethoxyethyl methacrylate in the copolymer.

In the Sundstrand pump test for distillate fuel oils, 1 liter of fuel oil containing 4 grams of synthetic sludge is treated with the additive. The oil is circulated for an hour through a Sundstrand oil burner pump containing a -mesh strainer. The sludge deposit is collected and weighed. A base oil gives 214 mg. of sludge whereas the same base oil containing 100 p.p.m. of this copolymer gives only 14 mg. of sludge.

A portion of the toluene solution of this copolymer is mixed with 100 SUS neutral oil and heated and stirred under reduced pressure to C. at 10 mm. to remove the volatile matter. The resulting oil solution, 29.4% of copolymer, shows a viscosity of 77.8 cs. at 210 F. An oil blend made up to contain 2.06% of said copolymer in a base oil shows viscosities of 7.20 cs. at 210 F. and 44.16 cs. at 100 F., representing a viscosity index of 129. The viscosity of the base oil is 5.56 cs. at 210 F. and 35.46 cs. at 100 F., with a viscosity index of 103.3.

Example 3 In a manner similar to that described in Example 2, there are copolymerized:

93.5 parts of lauryl-myristyl methacrylate, (96.3% pure by GLC),

10.0 parts of ethylsulfinyl(ethoxy) ethyl methacrylate,

50.0 parts of toluene,

0.2 part of azodiisobutyronitrile in 1.4 parts of chloroform and i 0.3 part of n-dodecyl mercaptan.

This charge is allowed to copolymerize under nitrogen at 89 to 93 C. during 6% hours total heating time; 12 incremental additions of 0.1 part of AIBN in 0.7 part of chloroform are added every 30 minutes beginning 45 minutes after the heating is started. The batch is finally diluted with 85 parts of toluene. The solids found as copolymer is 38.2%. This copolymer shows 1.08% sulfur representing 10.9% of ethylsulfinylpolyet-hoxyethyl methacrylate in the copolymer.

An oil blend containing only 0.125% of this copolymer disperses 0.4% of asphaltenes at 150 C. showing that the copolymer is an effective dispersant.

Some of the copolymer is transferred to 100 SUS neutral oil on stirring and heating a portion of the toluene solution of the copolymer with the oil to 125 C./ mm. This results in an oil solution consisting of 29.4% of copolymer. At 210 F., its viscosity is 107.9 cs. An oil blend is made up using this concentrate to make the blend 3.94% of copolymer. The base oil used has a viscosity of 5.56 cs. at 210 F. and 35.46 cs. at 100 F., with a viscosity index of 103.3. The viscosity of the blend is 9.42 cs. at 210 F. and 56.41 cs. at 100 F., with a viscosity index of 139.

Another blend composed of 1% of this copolymer, 2.0% of an overbased calcium sulfonate (300 base number), and 1% of zinc dialkyldithiophosphate in 100 SUS neutral oil is clear, indicating good compatibility.

When this copolymer is tested in the Sundstrand pump, using 100 ppm. of copolymer in the base oil, there results only 4 mg. of sludge in comparison to 226 mg. of sludge for the base oil without any copolymer.

A similar copolymerization was carried out using ethyl sulfinyl(ethoxy) ethyl 'methacrylate in place of the monomer containing 3.06 ethoxy units. The resulting polymer showed corresponding dispersant ability.

Example 4 Using the apparatus described in Example 2, a monomeric mixture is made up of:

101.2 parts of lauryl-myristyl methacrylate, (97.25% pure by GLC),

1.5 parts of ethylsulfinyl(ethoxy) ethyl methacrylate,

13.0 parts of toluene,

0.25 part of idiisopropyl benzene hydroperoxide, 50% active ingredient as furnished commercially and 0.06 part of lauryl mercaptan.

Example 5 In another run, performed in a manner similar to the procedure described in Example 4, except that more toluene is used, there are allowed to copolymerize:

42.2 parts of lauryl-myristyl methacrylate, (97.25% pure by GLC),

9.1 parts of ethylsulfinyl(ethoxy) ethyl methacrylate,

25.0 parts of toluene,

0.25 part of 50% solution of diisopropyl benzene hydroperoxide and 0.15 part of n-dodecyl mercaptan.

Twenty parts of toluene is added during the course of introducing this monomeric mixture to the polymerization vessel. Incremental additions of the hydroperoxide solution (50% active ingredient), of the 25% solution of quaternary ammonium chloride in n-hex-anol, of n-dodecyl mercaptan and of toluene added during the course of the copolymerization totals 0.25, 0.05, 0.15 and 12.5 parts, respectively. At 360 minutes, the batch is diluted to 37% of copolymer on the basis of the theoretical yield using 25.3 parts of toluene.

One percent of this copolymer in SUS neutral base oil gives a blend which shows a viscosity of 7.20 cs. at

210 F. and 42.64 cs. at 100 F., representing a viscosity index of 133.

In a second oil blend, only 0.125% of this copolymer in a neutral oil disperses 0.4% of asphaltenes at 150 C. indicating that it is an excellent dispersant for sludge in a mineral lubricating oil.

In the Sundstrand pump test, a base oil gives 230 mg. of sludge; the same base oil containing 100 p.p.m. of this copolymer gives only 31 mg. of sludge.

An oil blend containing 2% of this copolymer, 4.4% of a commercial barium phenate sulfide and 1% of zinc dialkyl dithiophosphate in 100 SUS neutral oil shows a slight hazy appearance with no copolymer settling out upon standing.

Example 6 Dilauryl-myristyl fumarate is prepared from a mixture consisting of 2% of n-decanol, 71% of n-dodecanol, 27% of n-tetradecanol and 1% of n-hexadecanol using direct esterifiaction of fumaric acid with p-toluene sulfonic acid as catalyst. The diester is obtained as a stripped residue which analyzes 0.03% ash. The acid number is 0 and the saponification number is 223.

A mixture composed of 71 parts of the dilauryl-myristyl fumarate, 24 parts of vinyl acetate, 5 parts of ethylsulfinyl(ethoxy) ethyl methacrylate, 2 parts of toluene and 1 part of t-butyl perbenzoate is heated at 100 C. and stirred under a nitrogen atmosphere for 2 hours. At 3 hours, 5 hours and 8 hours, 0.4 part of t-butyl perbenzoate in 5 parts of toluene is added and the temperature is kept at 100 to C. for a total of 16 hours. At 16 hours, 33 parts of toluene is added. The toluene solution which results is viscous and analyzes 57.3% solids as copolymer.

This copolymer is tested for dispersing action of asphaltenes in oil and found to be effective even at 0.125 of copolymer.

Example 7 Dilauryl-myristyl itaconate is prepared in a manner similar to that described in Example 6. The hydroxyl number on the mixed C C alcohol is used to calculate the theoretical saponification number of 225.6 for the diester. The saponification number found is 227.5. The alcohol mixture contains 71% of n-dodecanol.

A mixture is prepared from 47.5 parts of dilaurylmyristyl itaconate and 2.5 parts of ethylsulfinyl(ethoxy) ethyl methacrylate. Five parts of toluene, parts of diisopropylbenzene hydroperoxide, 50% strength as the hydroperoxide and 1 part of a 25% solution of didodecenyldimethylammonium chloride in n-butanol are added to the polymerization vessel with the monomers. copolymerization ensued at a batch temperature of 110 to 115 C. Additional hydroperoxide (50% solution), quaternary ammonium chloride (25 solution) and toluene are added as follows: at 3 hours, 1 part hydroperoxide solution, 0.2 part didodecenyldimethylammonium chloride solution with 2.5 parts of toluene; at 4 hours, 1.5 parts of hydroperoxide solution, 0.3 part of di-docenyldimethylammonium chloride solution; at 5, 6 and 7 hours, 1 part hydroperoxide solution, 0.2 parts didodecenyldimethylammonium chloride solution with 2.5 parts of tolu: ene, respectively. At 8 hours, the batch is diluted with 6 parts of toluene. A solution consisting of 55% copolymer is the product.

When this copolymer is used in blends to test for its effectiveness as a dispersant for sludge in mineral oils, it is found that only 0.25% of copolymer is needed to disperse 0.4% of asphaltenes.

Example 8 Using the apparatus described in Example 1, there is fed into the polymerization vessel during 120 minutes, the following mixture:

55 parts of vinyl stearate,

35 parts of vinyl acetate,

parts of ethylsulfinyl(ethoxy) ethyl acrylate,

0.05 part of n-octyl mercaptan,

5 parts of toluene and 0.3 part of a 50% solution of diisopropylbenzene hydroperoxide, as furnished commercially.

Three-tenths part of a 5% solution of t-octylphenoxyethoxyethylbenzyldimethylammonium chloride monohydrate in n-butanol is charged with the first thirty percent of the above monomeric mixture. The polymerization vessel is swept with nitrogen and heated by an electrically heated oil bath at 100 C. Beginning at 2.67 hours and through 6.7 hours, increments of a 50% solution of diisopropylbenzene hydroperoxide, of a 5% n-butanol solution of t-octylphenoxyethoxyethylbenzyldimethylammonium chloride monohydrate and of toluene are supplied to a total of 5.1, 3.5 and 25 parts, respectively. At 8 hours, the batch is diluted with 91 parts of toluene and heating is stopped. On allowing the batch to cool to ambient temperature, the clear viscous solution is analyzed and contains 41.25% of copolymer.

A portion (97 parts) of this copolymer solution is mixed with 97 parts of lubricating oil and heated and stirred to 105 C. under a reduced pressure of 10 mm. of mercury for 90 minutes. There results a concentrate comprising 28.3% of copolymer.

An oil blend is prepared containing 2% of this copolymer. It eiiectively disperses 0.4% asphaltenes in the standard asphaltenes test at 150 C.

Example 9 In another copolymerization carried out according to the procedure given for Example 2, there are allowed to copolymerize:

18 parts of cetyl-stearyl methacrylate, the methacrylic ester having been prepared from a commercial alcohol composed of 2% tetradecanol, 68% of octadecanol and 30% of hexadecanol,

18.5 parts of isodecyl methacrylate derived from commercial oxo-isodecanol,

8.75 parts of n-butyl methacrylate, and

4.75 parts of ethylsulfinyl(ethoxy) ethyl methacrylate.

The same copolymerization conditions are followed, as indicated in Example 2, using mercaptan and toluene, with azodiisobutyronitrile as the catalyst. The clear viscous solution analyzes 39.5% of solids as copolymer.

This copolymer is'an eifective dispersant. Only 0.5% of copolymer in a test blend disperses 0.4% of asphaltenes at 150 C.

One percent of this copolymer in a continental treated base oil gives an ASTM pour point of 35 F. Whereas the base oil without the copolymer gives an ASTM pour point of 0 F.

Several other oil solutions of this copolymer are obtained on stripping off the volatile matter. For example, 14.5 parts of the 39.5% solution is mixed with 21.1 parts of light hydraulic mineral oil, heated and stirred at 105 C. at 10 mm. for 60 minutes to give 28.6 parts of oil solution. This is a useful concentrate for blending with hydraulic oils to provide eflicient hydraulic fluids.

In another case, a mixture of 14.5 parts of the 39.5% solution and 20.6 parts of tributyl phosphate is stirred and heated to 100 to 105 C. at 10 mm. for 60 minutes to give a 20% solution of copolymer in the tributyl phosphate. This concentrate is useful in preparing hydraulic fluids where a phosphate is desirable.

These copolymers are also useful in synthetic lubricants. For example, 14.5 parts of the above toluene solution of copolymer is mixed with 17.9 parts of di-Z-ethylhexyl sebacate and heated and stirred, as above, to give 25.4 parts of a dispersant-type synthetic lubricant.

In another case, 14.5 parts of the aforementioned toluene solution is mixed with 20 parts of kerosene, heated and stirred at C. at 10 mm. for 30 minutes to give a 20% solution in fuel oil. This is useful as a concentrate for blending with fuel oils and gasolines to provide dispersancy and improved storage stability. In some cases, the volatile matter need not be removed.

A similar copolymerization was carried out using ethyl sulfinyl(ethoxy) ethyl methacrylate in place of the monomer containing 3.02 ethoxy units. The polymer so obtained also exhibited outstanding dispersant properties.

Example 10 The procedure of Example 4 is used with a starting mixture of 40.1 parts of lauryl-myristyl methacrylate, 6 parts of styrene, 2.5 parts of toluene, 0.2 part of a 50% solution of diisopropylbenzene 'hydroperoxide and 0.04 part of 25% solution of t-octylphenoxyethoxyethylbenzyldlmethylammonium chloride monohydrate. After polymerization for 2.25 hours, there is added over a 30 minute period a mixture of 4.5 parts of ethy1sulfinyl(ethoxy) ethyl methacrylate, 0.02 part of 50% solution of diisopropylbenzene hydroperoxide, 0.02 part of 5% solution of the above quaternary ammonium chloride in n-hexanol and 5 parts of toluene. The batch is kept at 105 to 114 C. for the next 4 hours and thereafter at 103 C. Increments are supplied of a 50% solution of diisopropylbenzene hydroperoxide, of a 5% solution of t-octylphenoxyethoxyethylbenzyldimethylammonium chloride monohydrate and toluene to totals of 0.22, 0.22 and 12.5 parts, respectively. Heating is discontinued at 6.25 hours. Then, 39 parts of toluene is added and the batch is allowed to cool to 30 C. with stirring. The resulting toluene solution contains by analysis, 43.2% of polymer. A toluene solution adjusted to 30% of polymer has a viscosity of 200 cs. at F.

A portion (69.7 parts) of the toluene solution (43.2% polymer) is stirred and heated with 64.4 parts of light lubricating oil for 90 minutes at 105 to C. under reduced pressure, finally at 10 mm. This results in 100.5

parts of oil solution which is 30% copolymer. Only 0.25% of this copolymer is needed to disperse 0.4% of asphaltenes at 150 C.

Example 11 In the same manner as in the preceding example, there is allowed to copolymerize 40.1 parts of lauryl-myristyl methacrylate with 4 parts of styrene. For the delayed addition, 4.5 parts of ethylsulfinyl(ethoxy) ethyl methacrylate is mixed with 2 parts of N-vinyl-2-pyrrolidinone, parts of toluene, 0.025 part of a 50% solution of diisopropylbenzene hydroperoxide and 0.025 part of a 5% solution of t-octylphenoxyethoxyethylbenzyldimethylammonium chloride monohydrate. Treatment for the duration of the preparation is the same as that given in the preceding example. The resulting toluene solution contains 44% copolymer. When this copolymer is used in a test blend, only 0.125% is required to disperse 0.4% asphaltenes at 150 C.

Example 12 A copolymerization similar to that of Example 4 was carried out using ethylsulfinylethovy(propoxy) 3,01 propyl methacrylate in place of the ethylsulfinyl(eth-oxy) ethyl methacrylate. The ethylsulfinylethoxy(propoxy) propyl methacrylate was obtained by reacting ethylsulfinylethanol with propylene oxide. Excellent dispersant ability was exhibited by the resulting copolymer.

We claim:

1. A viscous liquid to solid polymer of monoethylenically unsaturated polymerizable monomers comprising (a) about 0.5 to 60% by weight of a sulfoxide-containing monomer of the formula R is hydrogen or methyl, R is an alkeneoxy group of 2 to 5 carbon atoms, n is an integer having a value of 1 to 50, X is hydrogen or methyl, R" is an alkyl of 1 to 18 carbon atoms and (b) about 40 to 99.5% by weight of at least one ester of an (1) u,B-monoethylenically unsaturated polymerizable carboxylic acid and an alkanol having from 1 to 24 carbon atoms, benzyl alcohol, an alkyl-substituted benzyl alcohol or phenol or a (2) vinyl carboxylate of up to about 20 carbon atoms, said polymer being oil-soluble.

2. A polymer according to claim 1 wherein said (a) is ethylsulfinylpolyethoxyethyl methacrylate or ethylsulfinylpolyethoxyethyl acrylate.

3. A polymer according to claim 1 wherein said (b) is ,an acrylate or methacrylate of up to about 24 carbon atoms.

4. A polymer according to claim 1 wherein said (b) is an ester of acrylic or methacrylic acid with a mixture of about 70% lauryl alcohol and about 30% myristyl alcohol.

5. A polymer according to claim 1 wherein said (a) is is ethylsulfinylpolyethoxyethyl methacrylate and said (b) is lauryl-myristyl methacrylate.

6. A polymer according to claim 1 wherein said (a) is ethylsulfinylpolyethoxyethyl acrylate and said (b) is a mixture of vinyl stearate and vinyl acetate.

7. A polymer according to claim 1 wherein said (a) is ethylsulfinylethoxy polypropoxypropyl methacrylate and said (b) is lauryl-myristyl methacrylate.

8. A polymer according to claim 1 wherein said polymer comprises in an amount up to 15% by Weight of a vinyl pyrrolidinone, N-vinylpiperidinone, a vinyl caprolactam, dimethylaminoethyl acrylate or methacrylate, N (dimethylaminoethyl)acrylamide or methacrylamide, N,N-dimethylmethacrylamide, N-vinylsuccinimide or a vinyl pyridine.

9. A composition comprising a normally liquid hydrocarbon lubricant, fuel, and hydraulic fluid or liquid ester lubricant and hydraulic fluid and at least about 0.001% of the weight of the composition of a viscous liquid to solid polymer of monoethylenically unsaturated polymerizable monomers comprising (a) about 0.5 to 60% by weight of a sulfoxide-containing monomer of the formula CH2=O (R) 00001000110112 ISI-R X where R is hydrogen or methyl,

R is an alkyleneoxy group of 2 to 5 carbon atoms, n is an integer having a value of 1 to 50,

X is hydrogen or methyl,

R" is an alkyl of 1 to 18 carbon atoms and 12. A composition according to claim 9 wherein said liquid ester is di-Z-ethylhexyl sebacate.

13. A composition according to claim 9 wherein said (a) is ethylsulfinylpolyethoxyethyl methacrylate or ethylsulfinylpolyethoxyethyl acrylate.

14. A composition according to claim 9 wherein said (b) is an acrylate or methacrylate of up to about 24 carbon atoms.

15. A composition according to claim 9 wherein said (b) is an ester of acrylic or methacrylic acid with a mixture of about 70% lauryl alcohol and about 30% myristyl alcohol.

16. A composition according to claim 9 wherein said (a) is ethylsulfinylpolyethoxyethyl. methacrylate and said b) is lauryl-myristyl methacrylate.

17. A composition according to claim 9 wherein said (a) is ethylsulfinylpolyethoxyethyl acrylate and said (b) is a mixture of vinyl stearate and vinyl acetate.

18. A composition according to claim 9 wherein said (a) is ethylsulfinylethoxy polypropoxypropyl methacrylate and said (b) is lauryl-myristyl methacrylate.

References Cited UNITED STATES PATENTS 3,053,806 9/1962 La Combe et al. 260-79.3 3,100,748 8/1963 Richards et al 252-48.6 3,102,863 9/1963 Herbert et a1. 252-48.6 3,206,400 9/ 1965 Flowers et a1 252-48.6

DANIEL E. WYMAN, Primary Examiner.

L. G. XIARHOS, W. H. CANNON,

Assistant Examiners. 

9. A COMPOSITION COMPRISING A NORMALLY LIQUID HYDROCARBON LUBRICANT, FUEL, AND HYDRAULIC FLUID OR LIQUID ESTER LUBRICANT AND HYDRAULIC FLUID AND AT LEAST ABOUT 0.001% OF THE WEIGHT OF THE COMPOSITION OF A VISCOUS LIQUID TO SOLID POLYMER OF MONOETHYLENICALLY UNSATURATED POLYMERIZABLE MONOMERS COMPRISING (A) ABOUT 0.5 TO 60% BY WEIGHT OF A SULFOXIDE-CONTAINING MONOMER OF THE FORMULA 